Takhee Lee and co-workers demonstrate on p. 3071 that organic nonvolatile memory devices can be fabricated on flexible substrates. The organic nonvolatile memory devices show rewritable and nearly consistent switching characteristics, regardless of the bending circumstances. The stable switching performance of the organic memory devices with bending stress is a promising property, ultimately enhancing the possibility of the application for flexible organic memory devices.

Yan Xu and co-workers report on p. 3017 on a phospholipid polymer hydrogel that exhibits a remarkable ability to preserve cells on microfluidic chips without perfusion culture under cell-based assay conditions, with characteristics including maintenance of high cell viability, restraint of cell proliferation, and minimization of cellular function loss over a period of days and weeks. This material could establish a revolutionary flexibility for cellbased applications.

The increasing field of fluorescent materials for bioimaging and sensingapplications has generated a lot of interest for nanoparticles based on π-conjugated systems. This progress report highlights the important advancements achieved in the self-assembly of polymeric and discrete molecules, and the development of these nanoparticles toward advanced nanobiotechnological applications.

Polysaccharides have many biochemical and biomechanical functions that depend upon their nanoscale structure in their native biological contexts. Here we review recent developments in techniques to tune the assembly of polysaccharides at the nanometer length scale. This body of work is leading to new understanding of the emergent biological properties of polysaccharide nanoassemblies.

Article first published online: 25 MAY 2010 | DOI: 10.1002/adma.201000006

A 2-methacryloyloxyethyl phosphorylcholine (MPC) polymer hydrogel exhibits a remarkable ability to preserve cells on microfluidic chips without perfusion culture under cell-based assay conditions, with characteristics of maintenance of high cell viability, restraint of cell proliferation, and minimization of cellular function loss over a period of days and weeks. This would establish a revolutionary flexibility for cell-based applications.

Article first published online: 20 MAY 2010 | DOI: 10.1002/adma.201000155

A micro-demultiplexer of a coupled resonator optical waveguide composed of polystyrene microspheres is fabricated by a self-assembly technique in colloidal suspension on a lithographically patterned substrate. The spectrum of propagating light taken at the 60°-branch (Point 2) shows sharper peaks than that taken at Point 1 while the spectrum taken at the 30°-branch (Point 3) shows broader peaks.

A transparent stretchable conductor, in which well-aligned CNT ribbons are embedded in poly(dimethylsiloxane) (PDMS) (CNT/PDMS film), is presented. Due to the good inter-tube contact and stable CNT arrangement in the CNT ribbons, the CNT/PDMS film can maintain stable conductivity under repetitive stretching to strains up to 100%.

Polyfluorene based conjugated polyelectrolyte/silica nanocomposites are fabricated using sol-gel processing. Ionic termination groups on the conjugated polyelectrolyte lateral chains are shown to control the interaction at the inorganic-organic interface, leading to macroscale homogeneity and nanophase separation in a single material. The extent of nanophase separation is determined by the nature of the ionic groups, which may provide a means of controlling donor-acceptor distances in hybrid systems.

A novel type of extracellular matrices, stepwise adipogenesis-mimicking matrices, was developed from cultured mesenchymal stem cells controlled at different stages of adipogenesis. The matrices derived from stem cells, and the cells controlled at early and late stages of adipogenesis showed different effects on stem cell differentiation.

A polymer blend of a polyfluorene and an inert matrix is imaged with an innovative time-resolved confocal microscope. Local pump-probe signals (excited-state generation and deactivation) with sub-200-fs temporal resolution and 300-nm spatial resolution are measured. Peculiar dynamics at the interface between the segregated domains, invisible to standard optical microscopy, due to different inter-chain interactions and charge separation photophysics are detected.

A new MSNP-LTO anode is developed to enable a high-power battery system that provides three times more power than any existing battery system. It shows excellent cycle life and low-temperature performance, and exhibits unmatched safety characteristics.

Article first published online: 14 MAY 2010 | DOI: 10.1002/adma.201000591

Strategies are presented for forming inorganic, microscale light emitting diodes in interconnected arrays on plastic substrates, configured to accommodate extreme levels of bending, with negligible changes in the electrical properties or the emission wavelengths in the devices. The studies include quantitative analysis of the underlying mechanics and experimental measurements of bending induced shifts in the emission wavelength.

Horizontal alignment of single-walled carbon nanotubes (SWNTs) in large-area (square centimeter scale) films is achieved by a facile approach. Combining in situ arc discharge growth of SWNTs with a weak (0.56 T) magnetic field allows aligned SWNT films to be fabricated on various substrates, including flexible plastics. Moreover, the film size, thickness, location and orientation can all be controlled.

Article first published online: 31 MAY 2010 | DOI: 10.1002/adma.201000525

Highly luminescent, multiply passivated green- and red-light-emitting quantum dots are used as color converters in InGaN blue LEDs to achieve external quantum efficiencies of 72% and 34%, respectively. White QD-LEDs prepared for a display backlight are shown to have an efficacy of 41 lm W−1 and color reproducibility of 100% compared to the NTSC standard in CIE 1931. Finally, a 46 inch LCD TV panel (see image) using the QD-LED backlight is successfully demonstrated for the first time.

Excellent device characteristics are measured for a pentacene-based thin film transistor where the SiO2 gate dielectric is terminated with a self-assembled monolayer of 9,10-dinaphthylanthracene-2-phosphonate in which calculated molecular spacings are about 0.7 nm. This creates channels that are on the order of the “thickness” of an aromatic π system, which could allow for intercalation of pentacene units, favoring a π-stacking motif for this first pentacene layer.

The discovery of a reversed crystal growth route in zeolite analcime implies that crystal growth does not always follow classic theory. Aggregation of nanoparticles may dominate in early-stage crystal growth, followed by surface crystallization, and then extension from surface to core. Recent developments and evidence of such a novel phenomenon in other materials are discussed.